Question: Simplify the following expression: $p = \dfrac{9}{4k} + \dfrac{7}{5k}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $4k$ and $5k$ $\lcm(4k, 5k) = 20k$ $ p = \dfrac{5}{5} \cdot \dfrac{9}{4k} + \dfrac{4}{4} \cdot \dfrac{7}{5k} $ $p = \dfrac{45}{20k} + \dfrac{28}{20k}$ $p = \dfrac{45 +28}{20k}$ $p = \dfrac{73}{20k}$